边界形状对4股燃气射流扩展稳定性影响的数值模拟

为研究提高整装式液体发射药火炮燃烧稳定性的方法,从充液室结构出发,分析了冷态条件下边界形状对4股燃气射流扩展稳定性的影响。采用高速数字摄像系统,记录了4股燃气射流在5级圆柱渐扩型观察室中扩展过程。在此基础上,建立了气体与液体相互作用的三维非稳态数理模型,模拟了4股燃气射流在5级圆柱渐扩型、圆锥型和圆柱型观察室中扩展过程,获得了射流场三维两相分布图、压力和温度分布图。研究结果表明：4股燃气射流在5级圆柱渐扩型观察室中轴向位移的模拟值与实验结果较吻合;圆柱渐扩型和圆锥型观察室都可以增强燃气射流的径向扩展,有效抑制Taylor空腔与Helmholtz不稳定效应的正反馈机制;圆柱渐扩型由于台阶逐渐诱导作用,近喷孔处温度场无剧烈脉动,射流扩展更加稳定。     

双束燃气射流与整装式液体装药相互作用的实验和数值模拟

为了探索整装式液体发射药火炮(BLPG)内弹道稳定性的控制方法,设计了5 级圆柱渐扩型观察室和圆柱观察室,开展了双束燃气射流在液体药模拟工质中扩展的实验研究。实验结果表明,渐扩型结构能够抑制Taylor 空腔与Kelvin-Helmholtz 不稳定性效应的正反馈机制。在实验基础上,建立了三维非稳态数理模型,模拟了不同观察室结构下,双束燃气射流在液体工质中的扩展过程,获得了射流场中密度、压力和温度的分布图。模拟结果表明:圆柱渐扩型观察室中,由于渐扩台阶的诱导作用,强化了气液在径向的湍流掺混效应,抑制了射流的轴向湍流度;且射流的外轮廓相对较光滑。双束射流轴向位移的计算值与实验结果吻合较好。     

多股贴壁燃气射流在圆柱型充液室中的扩展特性

为了探索高温高压周向均布多股贴壁燃气射流在受限空间内液体工质中的扩展特性,设计了贴壁燃气射流在圆柱形充液室内扩展的实验装置。用数字高速录像系统记录多股贴壁燃气射流在充液室中的扩展过程,处理拍摄记录的射流扩展序列图,获得了不同时刻多股射流形态头部的平均轴向位移。从射流扩展序列图可以发现由Kelvin-Helmholtz不稳定性引起的表面不规则一直存在于整个射流扩展过程。通过改变喷孔个数和破膜喷射压力,对比分析了不同工况下多股贴壁燃气射流的扩展特性。结果表明:喷孔个数增加,相同时刻射流轴向扩展位移变小,t=5 ms时刻,从四孔增加到六孔,其轴向扩展位移减少了8.3%,从六孔增加到八孔,减少了3.1%;随着破膜喷射压力增大,射流轴向扩展速度更快,射流轴向扩展到达充液室顶部的时间变短,t=5 ms时刻,燃气破膜压力从12 MPa增加到20 MPa,射流轴向扩展速度增加了20.1%,从20 MPa增加到28 MPa,增加了19.9%。     

含能气体射流在液体工质中扩展的两维模型及数值模拟

为了研究整装式液体发射药火炮燃烧稳定性的控制方法,针对渐扩型药室结构,建立了含能气体射流在液体工质中扩展的两维模型,应用FLUENT应用软件对非稳态气体射流与液体工质相互作用的过程进行了模拟.探讨了渐扩型结构尺寸、喷气压力和喷口直径参数变化对射流扩展形态的影响,获得了射流场等温线、等压线和等密度线图.结果表明:当渐扩尺寸比为0.8、喷气压力大于30 MPa、喷孔直径大于2 mm时,气体射流发展不稳定,气液湍流掺混强烈.模拟出的射流轴向扩展速度和实验结果基本吻合.     

锥形多股火药燃气射流与液体工质相互作用的实验研究

为了解水下枪械的发射机理,设计了锥形多股火药燃气射流与水相互作用的模拟实验装置,借助高速摄像机研究了不同喷射压力、不同喷孔直径对多股燃气射流扩展特性的影响。实验结果表明:喷射压力增大,燃气射流的扩展速度增大,扩展过程中湍流不稳定性增强,气液卷吸程度加剧;喷射压力从10.8 MPa提高到28.8 MPa,中心射流的扩展速度增大28%,侧孔射流的扩展速度增大40%;中心喷孔直径由2 mm增大到3 mm,中心射流的扩展速度增大29%,侧孔射流的扩展速度增大26%,但射流的速度下降趋势更明显,而侧面喷孔直径的变化对射流扩展速度影响较小。     

圆柱型边界条件下多股燃气射流扩展形态的数值模拟

以整装式液体发射药火炮为背景,从气液两相湍流掺混出发,研究燃烧稳定性的方法。设计圆柱型观察室,采用数值模拟方法,基于流体动力学理论,分别模拟六股和八股燃气射流在圆柱型边界条件下的扩展。通过追踪燃气空腔的扩展,获得了射流场两相分布、流线分布及压力分布。模拟结果表明:2种工况下燃气射流的轴向位移相似,六股燃气射流外轮廓更为光滑,其径向发展强于八股燃气射流。八股燃气射流相互干涉对流场的影响较为剧烈,湍流掺混明显。2种工况下径向压力分布对比明显,轴向压力分布相似。     

喷射结构对充液圆管内气幕特性影响的数值分析

为了研究火炮水下气幕式发射过程中喷射结构对气幕特性的影响,建立了多股燃气射流在充液圆管中扩展的三维非稳态数理模型,获得了多股燃气射流在充液圆管内气液两相组分、压力与速度分布规律。计算结果表明:多股燃气射流从喷孔喷出后,在液体中形成多个Taylor空腔,通过Taylor空腔与液体湍流掺混生成管内气幕。由于气液湍流掺混作用导致流场内压力出现波动,汇聚界面产生低速涡流区域。斜面喷孔直径由1.5mm增大至2mm,斜面射流回流作用增强,导致由斜面射流与侧壁射流汇聚而成的侧面射流轴向扩张能力提升,气幕整体排水性能增强,8ms时气幕上方液体运动速度由8.26m·s-1增大至9.4m·s-1。     

脉冲等离子射流与液体工质相互作用特性实验研究及数值模拟

为了解等离子射流与液体介质间的相互作用特性,采用高速录像系统记录了等离子射流在圆柱充液观察室中的扩展过程,获得了等离子射流在液体介质中轴向、径向扩展位移及扩展速度随时间的变化特性。在实验基础上,建立了等离子射流在液体介质中扩展时的二维轴对称非稳态数学模型,并进行了数值模拟,获得了等离子体和液体两相体积分数时空分布特性,由两相体积分数时空分布图计算得到的Taylor空腔轴向扩展位移与实测值吻合较好。同时获得了射流场中的压力、速度和温度分布,并分析了Taylor空腔的间断机理。     

水下火炮气幕式发射过程中燃气射流与液体工质相互作用特性研究

为了研究水下火炮气幕式发射过程中燃气射流与液体工质相互作用的特性,设计了可视化模拟实验装置,采用高速录像系统记录了圆柱形充液室中弹丸运动及气体与液体相互作用的过程特性,得到了弹丸速度与气幕轴向扩展速度随时间的变化关系。对比不同喷射参数条件下实验结果可以发现：弹丸运动速度随着喷射压力的增加而增加;气幕减阻性能随着斜面喷孔尺寸增大得到提升,弹丸运动速度随之增大。在实验基础上,建立了弹丸运动条件下多股燃气射流在液体介质中扩展的三维非稳态数学模型。针对实验工况进行数值模拟,模拟结果中多股燃气射流扩展过程与实验结果一致;对比二者气幕顶部轴向扩展位移值,可以发现计算结果与实测值吻合较好。弹丸运动条件下气幕生成的数值模型的建立,为水下火炮发射过程中身管内气幕生成及减阻机理分析提供了参考。     

脉冲等离子射流在液体介质中扩展特性的测量与分析

为了深入了解液体工质电热化学炮的燃烧推进机理,设计了模拟实验装置。采用高速录像系统,观察了脉冲等离子射流喷入液体介质中的扩展过程。测量了脉冲等离子射流在液体介质中形成Taylor空腔的轴向位移和体积变化。得到了Taylor空腔体积随时间变化的定量扩展规律。讨论了贮液室边界形状、放电电压和喷嘴直径对等离子射流扩展的影响。结果表明,两相交界处由于湍流掺混形成皱褶不光滑的交界面。Taylor空腔扩展过程中出现了明显的振荡现象。渐扩结构因子由0.6减小到0.4,轴向位移第一峰值和体积第一峰值分别增大16.6%和12.4%。放电电压由3000 V减小到2100 V,轴向位移第一峰值和体积第一峰值分别减小36.1%和60.7%。喷嘴直径由2 mm减小到1.5 mm,轴向位移第一峰值和体积第一峰值分别减小27.2%和56.7%。     

Nitrosation and Nitration of Tetraacetyldibenzylhexaazaisowurtzitane

Tetraacetyldibenzylhitane (TADBIW) was subjected to debenzylation by nitrosating with inorganic materials available commercially to synthesize tetraacetyldinitrosohexaazaisowurtzitane (TADNSIW). TADNSIW was purified, and its structure was determined by FTIR, 1H NMR, MS and element analysis. The debenzylation reaction of TADBIW gave quantitative benzaldehyde as a by-product. This indicates that the reaction produces an imine cation as an intermediate. Hexanitrohexaazaisowurtzitane (HNIW) was prepared from unpurified TADNSIW with the yield over 96.0 % and the purity more than 98.0 %. And the mechanism of the reaction from TADNSIW to HNIW is proposed to be oxidation of nitroso and nitration of acetyl on the molecule of TADNSIW, This reaction system involved is simple, and the reaction can complete within a short time and under mild conditions. The product can be easily to separate and the waste disposed readily.     

A Robust Algorithm for Watermarking 2D Vector Maps with Low Shape-Distortions

The technique of watermarking has been introduced into 2D vector maps for many potential applications such as protecting the copyright of important GIS （geographical information system） data and tracing the data source of military maps. In most previous works, although the validity of the map data could be preserved during the embedding procedure, the shape-distortions of the map elements are usually neglected which would tend to degrade the invisibility of the watermarking schemes. A shape-preserving algorithm for watermarking 2D vector maps is presented in this paper. A 1D distance sequence extracted from the original map is adopted as the cover data instead of 2D coordinates. A watermark bit is represented by changing the distributions of the cover data. The embedding procedure induces lower shape-distortions than in former works. Experimental results indicate better invisibility of the proposed scheme, as well as its robustness to certain attacks such as map simplification, interpolation, additive noise and most geometric transforms.     

Open Rule-setting System Applied to Conceptual Design of Engines

Open rule-setting method advanced in this paper concentrates on providing designers of engines with a convenient way to express their design innovations and develop the expected prototypes in the early CAD stage, and constitute effective models for the following analysis process of CAE and CAPP. The problems arisen in the process of conceptual design with the traditional experience-based development method are analyzed. Based on those analyses, open rule-setting method is presented and some associated technical problems are discussed. The functional framework of open rule-setting system was built as software engineering methods. The speciality of the engine product as a kind of complex product and the requirement of the engine product based on its structural particularity to rule-setting system are considered carefully. A demonstration is supplied to illustrate how the open rule-setting method enhances the efficiency and quality of the engine conceptual design.     

Research on Linux Network Device Driver

By analyzing the working principle of Linux network device driver, discussing the Linux network driver structure and its key technologies, the general network driver structure and its design methodologies in Linux system are summarized. Through modifying the network device driver of Linux device driver 3rd version snull, c and improving the COW technology, the Zero-Copy technology in Linux （kernel version 2.6.11 ） is implemented. In the end, the success test tells us that the thorough analysis of network device driver is the foundation of many applications, and it also provides a certain improvement to a lot of real applications, even to military application development.     

Method for Measuring Velocity of Warhead Fragments Based on Photoelectric Detection

For measuring velocity and impacting position of single fragment of warhead, a non-contact measuring method is proposed, in which a six-light-screen array, a position indicator, a multi-channel chronograph and a computer are used.The principle of measurement is described. The key device of the system is a light screen array sensor which consists of six light screens allocated with certain geometrical parameters. When the fragment flies through the light screen array, the time of passing through each of the screens is recorded by the multi-channel chronograph. According to the time data and the geometrical parameters of the array, the velocity vector and the location of the fragment can be calculated immediately. The presented method can be used to locate the fragment and to measure the real velocity on its flying direction. It can also be used to measure the velocity of a fragment swarm after the system is engineered further.     

数码电子雷管中影响点火头性能因素分析

阐述了数码电子雷管中,点火药剂细结晶三硝基间苯二酚铅（LTNR）的制备工艺;从点火药剂的种类、加入黏合剂的质量分数、桥丝直径、点火头的电阻值、防潮漆的蘸涂等方面对点火头性能的影响因素进行了探讨;通过震动试验、并联起爆试验、延期精度检测与考核,试验结果表明：一次性合成的细结晶LTNR是制造数码电子雷管点火头较为理想的点火药剂,按技术要求生产的点火头性能指标能够满足行业标准要求。     

Improvement and Experiment of the Reamer in Vibra Cutter Against Wave Edge of Titanium Sheet Alloy Parts

By analyzing the influencing factors of part quality making of sheet alloy of titanium by vibra cutter, the shape of upper reamer is set as cylinder and wedge-shaped form, and the lower reamer as plain and hemicycle form, and its main structural parameters are defined as well. Then it is validated further that such improved vibra cutter reamer can be used to process curve-edged parts of titanium alloy sheet. The experimental result shows that the titanium alloy sheet parts processed by above equipment have no sharpen angles for convex parts and evident crevasse of concave-edged part. In summary, such improvement can eliminate the free-waved edge and improve the manufacture quality of titanium alloy sheet parts greatly.     

Algorithm for Multi-laser-target Tracking Based on Clustering Fusion

Multi-laser-target tracking is an important subject in the field of signal processing of laser warners. A clustering method is applied to the measurement of laser warner, and the space-time fusion for measurements in the same cluster is accomplished. Real-time tracking of multi-laser-target and real-time picking of multi-laser-signal are introduced using data fusion of the measurements. A prototype device of the algorithm is built up. The results of experiments show that the algorithm is very effective.     

Experimental Study on the Small Flyer Initiating Behavior of Fine-grained Explosives

The initiating behavior of fine-grained explosives by small flyer is studied. The diameter of small flyer in this device is 1 ram. The test results indicate that the granularity of explosives has great effect on its flyer initiating sensitivity.The flyer initiating sensitivity of the fine-grained explosives is higher and the critical initiating energy is lower than that of common explosives. For common explosive, the flyer initiating sensitivity increases as the density is reduced. But for the fine-grained explosive, the test results are exactly opposite.     

Influence of Installing Error on the Surface Shape Precision of the Axial Symmetry Aspheric Workpiece in Lapping

A method to calculate the surface shape error, which is caused by the installing error between the workpiece and the lapping tool in the process of form lapping, is proposed. The mathematical model which the installing translation error influences on the workpiece surface shape error is established. The changing rule of the error is simulated through the calculating example of the paraboloid workpiece. The results indicate that the surface shape error of the workpiece is increasing with the increase of the installing translation error, it is also increasing gradually along the center point of the curve surface to the edge, and the influence is severer to the curve surface with great curvature than that of the small curvature when the translation error is the same.